Judith,
I've never built a ceiling dial, but something doesn't sound right about the
advice that you got. The days that you choose should be days where the
"equation of time is 0 (sun time and watch time agree). This happens 4 times a
year. April 15, June 14, Sept 1, Dec 25. (sorry I shoul
Ron wrote:
<>
But clocks and dials DON'T coincide on these dates UNLESS you just happen to
live on your prime meridian.
If you want to apply the "normal" Equation of Time correction, you will have
to work out which days coincide at your own longitude.
Where I live (3 degrees West of Greenwich) c
Both Ron & Mike have got it almost right it seems..
If you intend to make a ceiling (or any other kind of dial) by connecting
the hour points shown by the shadow of the nodus on at least two of the four
days when EOT equals zero, then you would have a perfectly good dial that is
automatically cor
Hello Mike,
This is a bit confusing because I'm not sure I can tell what type of
hour-lines are being considered here. Perhaps Ron was referring to the
fact that if one constructs the hour-lines from the projection of the
Analemma itself AND includes the delta in local longitude from the
Mike, Luke,
I was saying, on a few of the days that the EOT is 0, look at your watch and
mark the ceiling right on the hour. And then connect all of the like hours
dots you will build a dial that works and is corrected for longitude, but not
EOT. The hour lines are simple straight ones, (tha
I think that I would pick a day near the winter solstice, apply both the EoT
AND longitude corrections for where I live and mark the hour spots.
Repeat at the summer solstice.
Then you would get the dial lines just like they are on (say) a horizontal
dial.
For example - the sun is shining today,
Ron, et al,
Yes, I like (and now think I understand) your approach, alas, I wish I
were patient enough. Namely, the hour angle of the Sun and its
projection will be what they are and no correction need be applied since
the EoT is zero and the hour angle delta between the local and standar
Hello Reinhold,
Very interesting, I used Altavista (URL below) to translate the URL you
sent. Thank you.
http://world.altavista.com/
Regards,
Luke Coletti
[EMAIL PROTECTED] wrote:
>
> Hello all,
>
> a good and easy way to build a ceiling-sundial is to use the
>
> Tridux 2000 by D
The past year, I've been playing around with a little 1cm. square mirror to
be used for ceiling sundials that Fred S. gave us at the Hartford NASS
conference.
I have a large room with a big ceiling. The roof of the house has an
overhang over the southern window, however. In order that the level m
D]>
To:
Sent: Saturday, December 29, 2001 3:30 PM
Subject: Re: Ceiling Sundial
> The past year, I've been playing around with a little 1cm. square mirror
to
> be used for ceiling sundials that Fred S. gave us at the Hartford NASS
> conference.
>
> I have a large room wit
Hi Fer
Thanks for pointing out the mirror sundial calculating feature of Zw2000.
But I see a problem with using it in practice, however.
Since a ceiling sundial uses a very small mounted mirror, I think that
measuring the exact inclination and declination of such a small mirror would
be very dif
Hi John and Everyone,
John mentioned:
"Also, there is the additional problem of physically transferring Zw2000
drawings and /or polar coordinates of hour angles and dial furniture onto the
ceiling."
I too have a mirror on the sash of my window for a future sundial on the
ceiling. O
Here's an alternative approach, which would work best with two people:
Set up a simple horizontal sundial, with declination lines, correctly
oriented, beside the mirror, say a foot to one side.
Using a laser pointer, or just a bare low-voltage filament lamp, cast a
shadow of the gnomon onto the su
Nice idea, John!
Moving the laser pointer a precise distance horizontally isn't really
necessary, nor exactly what you want. I think the requirement would be to
move the pointer along whatever axes you need to, but without changing
it's angular orientation. That way, you move from the pointer pro
;
To: "Sundial Mail List"
Sent: Wednesday, January 02, 2002 12:14 PM
Subject: Re: Ceiling Sundial
> Dave Bell contributed"
>
> >I had been thinking about John Lynes' suggestion for using a laser
pointer
> >to "copy" rays from a horizontal dial (or
Dave Bell contributed"
>I had been thinking about John Lynes' suggestion for using a laser pointer
>to "copy" rays from a horizontal dial (or any other type, for that matter)
>through a sill-mounted mirror to a ceiling dial. I'm attaching a (small!)
>sketch of the sort of 3D pantograph support it
I like it!! Printing the dial artwork on transparency film should work
well. Rub it down onto a thin sheet of glass supported in a frame, perhaps
with a film of water or the like to keep it in place. The frame would need
to be accurately leveled and oriented, but could easily be clamped in
positio
All of these ideas using lasers, auxiliary sundials and transparencies all
sound like they would help in drawing the sundial face, but I don't think
they will precisely place the dial drawing on the ceiling or help to
correctly align a declining or inclining mirror.
I think you all are minimizing
On Thu, 3 Jan 2002, John Carmichael wrote:
> All of these ideas using lasers, auxiliary sundials and transparencies all
> sound like they would help in drawing the sundial face, but I don't think
> they will precisely place the dial drawing on the ceiling or help to
> correctly align a declining
Dear Membership,
I've been listening to all the great ideas about Ceiling dials and
they all sound like they would work well under some circumstances.
In earthquake country or where the soil shifts from moisture/freezing
the mirror is going to have to be adjustable. If the dial is laid
out
I have seen much worthy comment on the above giving far more information
than I could possibly imagine.
However,
and please do take this to be a constructive comment,
Is it likely to have helped Judith in her quest
If I have missed something then please forgive me.
Regards
Andrew Pet
;; "sundial"
Sent: Friday, January 04, 2002 4:53 AM
Subject: Re: Ceiling Sundial
> I have seen much worthy comment on the above giving far more information
> than I could possibly imagine.
>
> However,
>
> and please do take this to be a constructive comment,
>
>
I agree, John.
At one solstice the EoT is about +2 minutes, and at the other it is about -2
minutes so there would be only a slight discrepancy. Too small to worry
about, especially as this is a junior school project and Judith is trying to
avoid too much complicated explanation.
I like her appr
day, January 04, 2002 9:31 AM
To: Andrew Pettit
Cc: sundial@rrz.uni-koeln.de
Subject: Re: Ceiling Sundial
Hi Andrew
As a former beginning dialist I know how Judith feels. While interesting to
the List, all of the ideas about transparencies, lasers, an auxiliary dials
probably just confused poor
Andrew,
The sundial list has served a dual purpose. The last note I got from Judith
said that she was going to use the original method of marking the ceiling,
using the new dates that I suggested. And, the discussion that followed seemed
to be interesting to a lot of people on the list. Look
On Fri, 4 Jan 2002, John Carmichael wrote:
> As a former beginning dialist I know how Judith feels. While interesting to
> the List, all of the ideas about transparencies, lasers, an auxiliary dials
> probably just confused poor Judith.
>
> As it turned out (in my opinion), her original idea was
blacktops in March (before Daylight
Savings in April). I believe this "community service" project should be
made available to all -- free of charge!
-Original Message-
From: Steve Lelievre [mailto:[EMAIL PROTECTED]
Sent: Friday, January 04, 2002 9:58 AM
To: sundial@rrz.uni-koeln.de
minutes are equal to the diameter of the reflected sunspot on your ceiling.
At 10:57 4-1-2002 -0400, Steve Lelievre wrote:
At one solstice the EoT is about +2 minutes, and at the other it is about -2
minutes so there would be only a slight discrepancy. Too small to worry
about, especially as th
Dear Dialists,
So, it looks like Fer de Vries suggestion to use something, his
program maybe, to at least be sure of the mirror placement being able
to project all the hour lines and declination lines wanted on the
ceiling rather than elsewhere is actually a very good idea.
I've never tried t
Andrew Pettit contributed,
>
>Is it likely to have helped Judith in her quest
>
As one of the 'guilty parties' I take your point Andrew but surely a
mailing list thread isn't just a straight Q&A device? It is an
opportunity to share know-how on all aspects of the subject in hand with,
h
be casting these
>sundials onto the area schoolyard blacktops in March (before Daylight
>Savings in April). I believe this "community service" project should be
>made available to all -- free of charge!
>
>
>
>-Original Message-
>From: Steve Lelievre [mail
I had been thinking about John Lynes' suggestion for using a laser pointer
to "copy" rays from a horizontal dial (or any other type, for that matter)
through a sill-mounted mirror to a ceiling dial. I'm attaching a (small!)
sketch of the sort of 3D pantograph support it would take. I'd appreciate
Wow!
The analysis of the limitations of polar ceiling sundials made by Fer
de Vries is just splendid. Essentialy the problem is: if we move the mirror
inwards it could fall under the ceiling shadow and thus produce no dot of
light,
and if we move it outwards the ray of light goes back outsid
Hi Anselmo, Fer, Ceiling Dialists,
This is a repeat of a message I sent earlier that bounced. My ISP sends my
mail with one of three addresses depending on which site I'm logged into, so I
changed my sundial address to this one: [EMAIL PROTECTED] Sorry if you receive
more than one copy of th
Dialing friends
The idea of
"mesh roofs" and {Snip:} "different mirrors in
multiple windows at multiple tiltings, coloring them
different colors by a dip in colored lacquer and
marking their spots with colored thumbtacks"
This reminds me of a comment my wife made to me after
I had stayed up a
Anton Reynecke wrote:
>
> I found out about the sundial mailing list from "Sundials on the Internet"
>
> I am interested in setting up a ceiling sundial with a mirror on a windowsill
> of a window facing North and can't find info on how to go about it, is there
> anyone who can help?
>
> Appr
36 matches
Mail list logo
